qemu-kvm/kvm-s390x-css-Refactor-IRB-construction.patch

From 0f4d8c51b51a23a87f1e3e9e764151352f652f3b Mon Sep 17 00:00:00 2001
From: Eric Farman <farman@linux.ibm.com>
Date: Thu, 24 Jun 2021 14:15:15 -0400
Subject: [PATCH 03/43] s390x/css: Refactor IRB construction

RH-Author: Miroslav Rezanina <mrezanin@redhat.com>
RH-Bugzilla: 1957194

Currently, all subchannel types have "sense data" copied into
the IRB.ECW space, and a couple flags enabled in the IRB.SCSW
and IRB.ESW. But for passthrough (vfio-ccw) subchannels,
this data isn't populated in the first place, so enabling
those flags leads to unexpected behavior if the guest tries to
process the sense data (zeros) in the IRB.ECW.

Let's add a subchannel callback that builds these portions of
the IRB, and move the existing code into a routine for those
virtual subchannels. The passthrough subchannels will be able
to piggy-back onto this later.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20210617232537.1337506-4-farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
(cherry picked from commit 0599a046acf1b625e97cef0aa702b5d86528c642)
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/s390x/3270-ccw.c    |  1 +
 hw/s390x/css.c         | 45 +++++++++++++++++++++++++++---------------
 hw/s390x/virtio-ccw.c  |  1 +
 include/hw/s390x/css.h |  2 ++
 4 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/hw/s390x/3270-ccw.c b/hw/s390x/3270-ccw.c
index f3e7342b1e..9efee591f9 100644
--- a/hw/s390x/3270-ccw.c
+++ b/hw/s390x/3270-ccw.c
@@ -130,6 +130,7 @@ static void emulated_ccw_3270_realize(DeviceState *ds, Error **errp)
                                 EMULATED_CCW_3270_CHPID_TYPE);
     sch->do_subchannel_work = do_subchannel_work_virtual;
     sch->ccw_cb = emulated_ccw_3270_cb;
+    sch->irb_cb = build_irb_virtual;
 
     ck->init(dev, &err);
     if (err) {
diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index fac7d5b39d..e77a0e523d 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -1651,6 +1651,30 @@ static void build_irb_sense_data(SubchDev *sch, IRB *irb)
     }
 }
 
+void build_irb_virtual(SubchDev *sch, IRB *irb)
+{
+    SCHIB *schib = &sch->curr_status;
+    uint16_t stctl = schib->scsw.ctrl & SCSW_CTRL_MASK_STCTL;
+
+    if (stctl & SCSW_STCTL_STATUS_PEND) {
+        if (schib->scsw.cstat & (SCSW_CSTAT_DATA_CHECK |
+                        SCSW_CSTAT_CHN_CTRL_CHK |
+                        SCSW_CSTAT_INTF_CTRL_CHK)) {
+            irb->scsw.flags |= SCSW_FLAGS_MASK_ESWF;
+            irb->esw.word0 = 0x04804000;
+        } else {
+            irb->esw.word0 = 0x00800000;
+        }
+        /* If a unit check is pending, copy sense data. */
+        if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) &&
+            (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) {
+            irb->scsw.flags |= SCSW_FLAGS_MASK_ESWF | SCSW_FLAGS_MASK_ECTL;
+            build_irb_sense_data(sch, irb);
+            irb->esw.erw = ESW_ERW_SENSE | (sizeof(sch->sense_data) << 8);
+        }
+    }
+}
+
 int css_do_tsch_get_irb(SubchDev *sch, IRB *target_irb, int *irb_len)
 {
     SCHIB *schib = &sch->curr_status;
@@ -1669,23 +1693,12 @@ int css_do_tsch_get_irb(SubchDev *sch, IRB *target_irb, int *irb_len)
 
     /* Copy scsw from current status. */
     irb.scsw = schib->scsw;
-    if (stctl & SCSW_STCTL_STATUS_PEND) {
-        if (schib->scsw.cstat & (SCSW_CSTAT_DATA_CHECK |
-                        SCSW_CSTAT_CHN_CTRL_CHK |
-                        SCSW_CSTAT_INTF_CTRL_CHK)) {
-            irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF;
-            irb.esw.word0 = 0x04804000;
-        } else {
-            irb.esw.word0 = 0x00800000;
-        }
-        /* If a unit check is pending, copy sense data. */
-        if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) &&
-            (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) {
-            irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | SCSW_FLAGS_MASK_ECTL;
-            build_irb_sense_data(sch, &irb);
-            irb.esw.erw = ESW_ERW_SENSE | (sizeof(sch->sense_data) << 8);
-        }
+
+    /* Build other IRB data, if necessary */
+    if (sch->irb_cb) {
+        sch->irb_cb(sch, &irb);
     }
+
     /* Store the irb to the guest. */
     p = schib->pmcw;
     copy_irb_to_guest(target_irb, &irb, &p, irb_len);
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 8195f3546e..5a1eb39325 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -754,6 +754,7 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
     sch->id.reserved = 0xff;
     sch->id.cu_type = VIRTIO_CCW_CU_TYPE;
     sch->do_subchannel_work = do_subchannel_work_virtual;
+    sch->irb_cb = build_irb_virtual;
     ccw_dev->sch = sch;
     dev->indicators = NULL;
     dev->revision = -1;
diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index bba7593d2e..7c23a13f3d 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -138,6 +138,7 @@ struct SubchDev {
     int (*ccw_cb) (SubchDev *, CCW1);
     void (*disable_cb)(SubchDev *);
     IOInstEnding (*do_subchannel_work) (SubchDev *);
+    void (*irb_cb)(SubchDev *, IRB *);
     SenseId id;
     void *driver_data;
 };
@@ -215,6 +216,7 @@ void css_clear_sei_pending(void);
 IOInstEnding s390_ccw_cmd_request(SubchDev *sch);
 IOInstEnding do_subchannel_work_virtual(SubchDev *sub);
 IOInstEnding do_subchannel_work_passthrough(SubchDev *sub);
+void build_irb_virtual(SubchDev *sch, IRB *irb);
 
 int s390_ccw_halt(SubchDev *sch);
 int s390_ccw_clear(SubchDev *sch);
-- 
2.27.0